Package name - how do you set a custom package name?

[Anke]

In order to be able to release an app in the Play Store, at least the following requirements must be met:

1. The version code is higher than the current version.
2. The packageName is the same (as the previous / original one).
3. The keystore is identical (with the previous / initial version).
4. The targetSdkVersion corresponds to the minimum SDK required by Google (from Aug 2021: SDK 30 for new apps and from Nov 2021 also for updates).